I propose to learn a new laboratory technique - cavity ring-down spectroscopy - to start a new direction in my research. Since arriving at Kalamazoo, I have studied the photon-initiated decomposition of molecules that contain nitric oxide, NO. It is an easy molecule to detect and the spectra are straightforward to analyze. Cavity ring-down spectroscopy will help me jump into a broader range of photochemistry projects by allowing me to detect more than just NO. To gear up for cavity ring-down spectroscopy, I need some supplies and time to learn to use the technique as well to become better versed in spectroscopy. After we establish that we can run the cavity ring-down experiment we will measure the vibrational energy deposited into O2 from the light-induced decomposition of NO3. Eventually, we will look for HNO produced by a molecular elimination from methyl nitrite, a speculative experiment using cavity ring-down spectroscopic detection. Adding a new detection technique will invigorate my research as I explore nature in new ways.